Pump for internal-combustion engines.



A. F. MACDONALD.

PUMP FOB. INTERNAL COMBUSTION ENGINES.

APPLICATION FILED NOV. 9 ,1912.

Patented Feb.9,1915.

Invent-,5 F. Macdonald Armanr. 'mecnonnnn, or SCHENECTADY, NEW YORK, ASSIGNOR T GENERAL -ELECTRIC COMPANY, A CORPORATION OF NEW YORK,

PUMP FOR- INTERNAL-COMBUSTION ENGINE-S.

Specification of Letters Patent.

Patentedreb.9,1lu1l5.

Application filed November 9, 1912. Serial No. 730,324. I

'-certain new and useful Improvements in Pumps for Internal-Combustion Engines,

' of which the following is a specification.

The present invention relates to fuel pumps for internal combustion engines and especially 'to th'e means for controlling the delivery thereof and has for its object to improve the construction and operation of the same.

7 My invention is intended more especially for use with high compression engines op erating on the constant pressure plan. That is to say engines wherein relatively pure air is compressed. to a temperature above the igniting temperature of the fuel which is injected at or about the outer dead center by a blast of air or-other gas, the introduction being by a pulverizer, injector, or atomizer, subject to the control of a needle valve. The pump is arranged to deliver fuel, such as a crude oil, to the 'pulverizer against the high blast pressure during the period that the needle valve is closed, and subsequently when the valve is opened the blast pressure discharges the fuel into the combustion space of the engine. In such an engine fuel has-to be delivered thereto.

in measured quantities in accordance with the load requirements. In practice this has been accomplished by controlling the action of the suction valve of the pump by changing the :position ofthe -fulcrum of a lever that is vibrated by and in synchronism with the pump plunger, said fulcrum being supported solely "by a rod leading to the speed governor. rectly imposesan intermittent load more or less great on the governor, first in one direction and then in another which frequently causes it to hunt unless made large and powerful. I aim to improve the governing effect by a novel arrangement of 'parts as will appear hereinafter.

For a consideration of what I believe to be novel and my invention, attention is di 1 is a view partly in elevation and partly.

Such an arrangement diin section of my improved pump governing mechanism; Fig. 2 is a diagram illustrating the action of the mechanism; Fig. 3 is a detailed view of a slight modification, and Figs. 4 and 5 are modifications showing means for changing the timing of the suction valves.

4: indicates a shaft, such for example as the cam shaft of aninternal combustion engine. Keyed to the shaft is an eccentric 5 and surrounding it is an eccentric strap 6 that is connected to'a sliding cross-head 7, the latter being guided by the guides 8. Connected to the cross-head is a reciprocating pump plunger 9. The lower end of the plunger enters a cylinder 10 in the pump casing, the latter being providedwith a suction valve 11, and a dischar "e valve 12. The

pump preferably has ,a dis lacement which is considerably greater than is required to supply the maximum amount of fuel to the engine. This is advantageous because it avoids too great a refinement in the regulation and also because it minimizes the effect of leakage around the piston and past the valves. ply chamber 13 by the pipe 14 connected with any suitable source, and is discharged to the pipe 15 leading in the present case to a fuel pulverizer, atomizer, or injector opening into the engine cylinder. The suction valve is provided with a depending stem 16 and situated below it is a lifter 17 containing an adjustable screw 18 that engages the lower end of the valve stem for the Fuel is admitted to the suppurpose of raising and holding the suction v ed by gravity, or it may be seated partly by gravity and partly by a light spring 19.

The lifter is mounted on a spindle 20 which projects through .the wall of the chamber 13 andha's attached thereto an arm '21. Theparts '17, .18 and 21 may for convenience be termed a lifter because, although separate, they move as one element. To the outer end of the arm is connected a .rod 22,

the upper end of which is provided with a pin 23 arranged to slide in the slot 24 in the lever 25. This lever isprovided with a fixed fulcrum '26 carried'by anyv .sultable support,

no i

I such for exampleas a part of the engine frame 27. Thus it will be seen that the reactions. of the lever due to the reversal of the direction of motionof the cross-head are transmitted to the fulcrum and not to the speed governor as heretofore has been the general practice. The right hand end of the lever is provided with a fork'that em- Y braces a pivoted'block 28, the latter being carried by the'cross-head 7 so that as the cross-headv moves up and down the lever will be vibrated in synchronism therewith,

always having a definite stroke in a definite main shaftof the engine. As the weights of the governor move in and out due to speed variatlon the upper end of the rod 22 is moved toward and away from the crosshead so that the point of application of power of the vibrating lever to the rod 22 is changed. That is. to say the position of the pin 23 coincides with the point of application of power of the lever to the rod and this pin is moved back and .forth in the slot 24 to change the amount of fuel delivered to the engine. The result of this is to change the effective length of the rod 22, said effective length being greatest when the rod is in an upright position and gradually growing less as it is moved to the left. As shown the control of the suction valve is automatic,

' I but if it be desired to control the engine by hand, as is desirable in some cases, the

upper end of the rod 22 may bemoved back and forth by hand, as for example by means of a link 29, a locking device being provided where necessary.

In Fig. '3 is shown a slight modification wherein'25 indicates the lever which is' vibrated by the cross-head and 26 the fixed pivot therefon. 22indicates the rod which 18 provided w th a head 34 carrying rollers 35 suitably supported on pivots and engaging the top and bottom surfaces of the lever.

The head is slotted at 36 so that it can pass over the projecting pivot 26. This arrangementreduces friction and in some cases permits of a shorter lever.

Referring to Fig. 2 which indicates diagrammatically the action of my invention,

25 is the constantly vibrating lever and 26 its'fixed pivot. 21 indicates the arm for moving the suction valve lifter 17 the latter having been omitted for simplicity since said arm and lifter have the same movements. 11 indicates the suction valve whichis shown as resting on'its seat and 16 the stem therefor. 22 indicates the 'rod which is hinged to the arm 21 at its lower end and is adjustable or movable to and fro on the lever 25. The position of the rod indicates that the supply of fuel to the engine is at or about the minimum. Swinging the upper end of the rod to the right will increase the supply of fuel because the suction valve 11 will be permittedto close at an earlier part of the discharge stroke of the plunger and hence more fuel will be discharged through the valve 12. During the portion of the plunger stroke that the arm 21 is above the position shown the suction valve will be open, and during the portion of the stroke that the arm is below the stem of the valve it will be closed. Moving the upper end of the rod 22 to the left from its upright position has, as before stated, the effect of shortening the connection between the lever 25 and the arm 21. I may accomplish this result by. the arrangement shown in Fig. 4

wherein the rod 22 is made in two parts, each of which is provided with a screw threaded end 37, the threads on one part being left handed and those on the other right handed. These threads should have a quick pitch to give a considerable longitudinal movement of the parts of the rod for a small angular movement of the nut 38, the

latter being connected by the arm 39 to the link 29 previously referred to. It is also preferable to employ double or triple screw threads to reduce wear. The upper end of the rod will in this case, be pivotally united to the lever 25 instead of sliding therpon.

Fig. .5 shows another arrangemeIrtNsI itable for use where a considerable lengthwise movement of the parts of the rod 22 is desired. The adjacent ends of the rod are provided with rack teeth 40 that mesh with a' gear 41 carried by a holder 42 which also guides and holds the parts of the rod in alinement. To the spindle of the gear is attached an arm that is connected to the op crating device 29. I have only shown one pump plunger and its valves but it is to be understood that they can be duplicated at will and that all the suction valve lifters will be moved by the rod 22.

From the foregoing it will be seen that the vibrations of the lever 25 do not affect the speed governor and that the only load imposed on said governor is that of moving f the upperend of the rod 22 or changing its length to vary its effective action. Inasmuch as the pump, is of the reciprocating type, the governor can easily adjust the position of the pin' 23 or changethe length of the rod when there is no load on it, i. c.

at the instant of reversal of the direction other advantage in my construction over the prior art is found in the fact that the work of moving the suction valve and of holding it off of its seat against the pressure of the fluid discharged. by the plunger on itsworking stroke is done by the lever, and hence all ,the governor has to do is to shift onev In accordance with the provisions of the patent statutes,'I have described the principle of operation of my invention, together with the apparatus which I now consider to represent the best embodiment thereof; but I desire to have it understood that the apparatus shown is only illustrative, and thatv the invention can' be carried out by other means.

What I claim as new and desire to secure by Letters Patent of the United States, 1s

1. In combination, a cylinder, a plunger therefor, suction and discharge valves for the cylinder, a lever that is vibrated in synchronism with the pump plunger, a fixed fulcrum for the lever, a member for varying the portion of the discharge stroke of the plunger that the suction valve is held off of its seat, and connecting means interposed between the lever and member which is adjustable to change the timing-of the suction valve.

2. In combination, a cylinder, a plunger therefor, suction and discharge valves for the cylinder, a lever that is vibrated in synchronism with the pump plunger, a fixed fulcrum for. the lever, a member for varying the portion of the discharge stroke of the plunger that the suction valve is held off of its seat, a connection between the lever and member, and a speed responsive device for varying the "effective action of said lever and connection on the member.

3. In combination, a cylinder, a plunger therefor, suction and discharge valves for .the cylinder, a'lever that is vibrated in synchronism with the pump plunger, a fixed fulcrum for the lever, a rod acting to hold the suction valve off of its seat for a portion of the discharge stroke-of the plunger, said rod being .operatively connected to and moved by the lever, and means for changing the effective length of the rod to vary the time of closing of the suction valve.

4. In combination, a' cylinder, a plunger therefor, suction and discharge valves for the cylinder, a lever that is vibrated in syn-- chronism with the pump plungers, a fixed fulcrum for the lever, a'lifter for the suctionvalve, a rod'connecting the lifter and lever, and means for adjusting one end of the rod to vary the point of application of power of the lever to said rod.

5. In combination, a cylinder, a plunger therefor, suction and discharge valves for.

the cylinder, a lever that is vibrated. in synchronismwith the pump plunger, a fixed fulcrum for the lever, an arm for actuating the suction valve, a rod connecting the arm and the lever, and a. speed governor which slides one end of the rod on the lever to vary the application of power of the lever to therod. p

6. A fuel pump for internal combustion engines comprising a cylinder and plunger therefor which displaces on each stroke a cons1derably greater amount of fuel than 1s necessary for the maximum load of the engine, suction and discharge valves for the cylinder, a lifter for the suction valve, a

the latter, and means for changing the effective action of the rod on the lifter.

8. In combination, a cylinder, a plunger therefor, suction and discharge valves for "the cylinder, a means for reciprocating the .plunger, a lifter for the suction valve, 9.

member vibrated in synchronism with the pump plunger, a connector between the member and the lifter, and means for moving one end of said connector to change the effective action of the member on the lifter. 9. In combination, a' cylinder, a plun er therefor, suction and discharge valves .or the cylinder, a means for reciprocating the plunger, a lifter for the suction valve, a member vibrated in synchronism with the pump plunger, a rod which connects the member and the lifter and is pivotally secured to one of them, and means for sliding one end of the rod with respect to its cooperating element to change the effective action of the member on the lifter.

10. In a pump, the combination of a cylinder, suction and discharge valves therefor, a plunger, a lifter for the suction valve, a

lever for moving the lifter, a rod that reing movable to change the timing of the suetion valve, and means for moving the last .named end of the rod.

11. In a pump, the combination of a cylinder, a plunger, suction and. discharge 'valves therefor, a lifter for the suction valve, alever for moving the lifter, a memher which moves in synchronism with the plunger, a rod which directly connects the lever and member, means pivotally uniting the rod to one of said parts, means slidably connecting the rod to the other of said parts, and means connected to said rodfor sliding one of its ends on its cooperating part.

12. In combination, a cylinder, a plunger therefor, suction and discharge valves for the cylinder, a lever that isvibrated in syn- I chronism with the pump plunger and has a constant length of stroke in a fixed region, a fixed fulcrum for the lever, a lifter that is adjustable to vary the portion of the dis- ALEXANDER F. MACDONALD.

Witnesses.

BENJAMIN B. HULL, HELEN Onronn. 

